NORWALK -- A 29-year-old Salvadorian sex offender was sentenced Friday at U.S. District Court in Hartford to 37 months in prison for an immigration violation.

Danilo Alvarado-Carbajar was convicted of illegally reentering the United States following deportation. He pleaded guilty to the crime on Dec. 13, 2012.

Alvarado-Carbajar was convicted of second-degree sexual assault in October 2006 at Stamford Superior Court and sentenced to nine months in prison. After finishing his prison sentence in May 2007, he was deported to his native El Salvador, court documents show.

Sometime thereafter, Alvarado-Carbajar re-entered the United States without receiving consent from the proper authorities, according to an affidavit.

Norwalk Police arrested Alvarado-Carbajar on June 22, 2012 for a probation violation and found out that he was in the country illegally. He has been detained his arrest.